As conventional bus-bar fastening structures, there have been known bus-bar fastening structures which are disclosed in JP-A-2004-227928(PTL1), JP-A-2000-067833(PTL2), JP-A-2005-229755 (PTL3) and JP-A-8-322125 (PTL4), for example.
Namely, in PTL 1, as is shown in FIG. 11, PTL1 describes a structure in which one end 110A of a bus-bar 110 is connected to a negative pole pillar 100 by fitting the one end 110A on the negative pole pillar 100 and thereafter screwing a nut on to a thread portion 100A of the pole pillar 100, while the other end 110B of the bus-bar 110 is connected to a power supply breaker situated outside the figure. Note that in the figure, reference numeral 120 denotes a holder made of a synthetic resin, 121 a bus-bar sealing portion where the bus-bar 110 is sealed, 130 a lithium ion battery (a secondary battery), and 140 a service plug mounting portion.